PROJECT SUMMARY: COG 2017: State of the Science: Healthy Weight Maintenance during Pediatric and Adolescent Cancer Treatment The Nutrition Committee within Children's Oncology Group (COG), a National Cancer Institute supported clinical trials group, has the scientific charge of advancing nutritional science within pediatric oncology with the objective of further improving clinical outcomes, reducing nutritional-related toxicities, and improving patient reported outcomes. Nutritional status has emerged as a poor prognostic indicator in pediatric and adult cancer populations, yet little attention is directed towards the nutritional needs and research gaps among children, adolescents, and young adults with cancer. With the majority of children diagnosed with cancer surviving their disease, it is evident that more research is needed in this understudied area. We are proposing to hold a conference on the State of the Science: Healthy Weight Maintenance during Pediatric and Adolescent Cancer Treatment on September 11, 2017 in Atlanta, Georgia. The meeting will be held immediately prior to the annual COG meeting providing a unique opportunity for multidisciplinary interaction between nutritional investigators, oncologists and stem cell transplant physicians, allied health professionals and translational scientists in the area of cancer, nutrition, and related scientific fields. This conference was developed by the Nutrition Committee of COG and has obtained approval from the leadership of COG. The 2017 Scientific Organizing Committee has assembled a talented faculty panel to serve in its planning and established experts have agreed to serve as invited speakers. The plenary sessions and topics have been carefully selected and are identified as areas that are fundamental to understanding when considering the design and conduct of a nutritional clinical trial in pediatric oncology. The objectives of this meeting are to learn about nutritional conditions in the pediatric population, understand mechanisms and biomarkers associated with nutritional conditions, understand the application of these factors in underserved/minority and young adult populations, and cultivate the next generation of nutritional scientists. At the conclusion of our meeting, we will agree on the principles for protocol development in the area of nutritional science and pediatric oncology within COG. We plan to disseminate the information learned from this meeting with a series of published manuscripts summarizing the conference proceedings in a pediatric oncology or nutrition-related journal.